O-Chlorobenzylidene malononitrile (CS) is a well-known riot control agent used by law enforcing agencies during civil disturbances and one of the most potent lachrymator skin irritants. CS was synthesized via Knoevenagel condensation of o-chlorobenzaldehyde with malononitrile in the presence of different bases as a catalyst in water (U.S. Pat. No. 7,732,631).
Pyrotechnic compositions are composed of an inorganic oxidizer (potassium chlorate, nitrate or perchlorate) and a combustible organic fuel (lactose or sucrose) to chemically generate heat, light or color. Some additives facilitate burning and improve the processing of the composition. Stabilizer avoids drowning of the compositions owing to melting of one of the constituents. Metal oxide or carbonates such as magnesium carbonate or magnesium hydroxide are widely used as a stabilizer and coolant. Organic dyes such as 1,4-dihydroxy anthraquinone (orange), 1-(p-tolylamino)-4-hydroxy anthraquinone (violet), 1-methylamino anthraquinone (red), and 4,4′-methylidyne-bis-3-methyl-1-phenyl-2-pyrazolin-5-one (yellow) are used in smoke compositions. Binders are widely used to prevent segregation of oxidizers and fuels in pyrotechnic formulations.
Use of a binder also increases the homogeneity of a mixture and possibility of successful ignition. Polymers have been incorporated into pyrotechnic and propellant compositions as binders to improve mechanical properties, sensitivity and manufacturing output of the compositions.
There have been recent efforts to develop pyrotechnic disseminating riot control composition with various specialty binders. Polyester resin (Bryant et. al. U.S. Pat. No. 3,391,036) was used to obtain solid and desired shaped charges. Other polymeric binder based on aromatic sulphur containing epoxy resin was disclosed in Drake et. al. U.S. Pat. No. 3,712,233 which described caseless munition for the dissemination of CS without flaming Kramer patent no. DE 3418116 C1 describes pyrotechnic composition including CS or CN as irritant and polyvinyl acetate as binder to obtain desired shaped munitions. Aliphatic sulfur-containing organic compound cured with aliphatic sulfur containing epoxy resin (Flynn et. al. U.S. Pat. No. 4,190,471), non-halogenated epoxy based resin cured with an organic acid or organic acid anhydride (Kott et. al. U.S. Pat. No. 3,704,187) and liquid epoxy based resins with an organic amine curing agent (Wernett et. al. U.S. Pat. No. 3,467,558) were used in riot control compositions as binders.
Known riot control compositions do not meet the need for compositions which have a low ignition temperature and toxicity. Many disclosed compositions may release toxic and corrosive decomposition products (e.g. hydrogenated or aromatic halogen, hydrogen sulfide) during combustion.